docs: compile-by-default, hybrid fallback, AOT; mark staged path 1/2/5 done

README and the self-hosting design doc now describe the current pipeline:
compile-by-default with an always-correct interpreter fallback, var-cell late
binding, parity validation, and AOT images. The staged path marks
var-indirection, hybrid+coverage, and compile-by-default+AOT done; self-hosting
the compiler and moving core to Clojure remain.

README.md

@@ -2,7 +2,7 @@
 
 [![tests](https://github.com/jolt-lang/jolt/actions/workflows/tests.yml/badge.svg)](https://github.com/jolt-lang/jolt/actions/workflows/tests.yml)
 
-A Clojure interpreter running on [Janet](https://janet-lang.org). Jolt reads Clojure source, evaluates it with an interpreter written in pure Janet, and ships a Clojure-compatible standard library. The goal is a Janet-hosted [SCI](https://github.com/borkdude/sci) runtime — a minimal bootstrap that loads SCI's Clojure source as its standard library.
+A Clojure implementation on [Janet](https://janet-lang.org). Jolt reads Clojure source and, by default, compiles each form to native Janet bytecode — falling back to a tree-walking interpreter for forms the compiler doesn't handle, so results always match the interpreter. It ships a Clojure-compatible standard library. The goal is a Janet-hosted [SCI](https://github.com/borkdude/sci)-style runtime with a minimal bootstrap.
 
 ## Build
 
@@ -61,51 +61,48 @@ hello 42
 
 ### Evaluation pipeline: interpreted and compiled
 
-Every form Jolt evaluates passes through one router (`eval-one`), which decides
+Every form passes through one router (`loader/eval-toplevel`) that decides *per
-*per form* whether to tree-walk it or compile it to Janet. There are two modes:
+form* whether to tree-walk it or compile it to Janet bytecode. The shipped
+runtime **compiles by default**; set `JOLT_INTERPRET=1` to force the interpreter.
 
-**Interpreted (default).** Without `:compile?`, every form is evaluated by the
+**Hybrid, always correct.** The compiler is incomplete by design: a form it can't
-tree-walking interpreter (`eval-form`). This is the live, fully-featured path:
+compile correctly throws `jolt/uncompilable`, and the router falls back to the
-all of Clojure's semantics — macros, multimethods, protocols, dynamic vars,
+tree-walking interpreter (`eval-form`) for that form. So the result *always*
-lazy seqs, destructuring — go through here.
+matches the interpreter — compilation is a transparent speedup, never a semantic
+change. Only the compile step is guarded; runtime errors in compiled code
+propagate normally (no double-evaluation, no hidden errors).
 
-**Compiled (`:compile? true`).** With compilation enabled, the router splits each
+What compiles: `def`/`defn`, multi-arity / named / variadic fns, `recur` (in
-top-level form two ways:
+`loop` and directly in `fn`), `let`/`if`/`do`/`try`/`throw`/`quote`, map and
+vector literals, and calls. What falls back to the interpreter: context-modifying
+and definitional forms (`ns`, `defmacro`, `deftype`, `defprotocol`,
+`defmulti`/`defmethod`, `reify`, `require`, `binding`, …), destructuring, regex
+literals, and the handful of interpreter-only special forms.
 
-- **Context-modifying forms always interpret.** `ns`, `defmacro`, `deftype`,
+**Live redefinition.** Compiled global references deref through Jolt **var cells**
-  `defmulti`/`defmethod`, `require`, `in-ns`, `set!`, `var`, `.`, `new`, `eval`,
+(Janet early-binds plain symbols, which would freeze redefinition), so redefining
-  and syntax-quote mutate the evaluation context (namespaces, the macro table,
+a `def`/`defn` at the REPL is visible to already-compiled callers — Clojure's var
-  type/method registries, dynamic vars), so they are routed to the interpreter
+model. Hot numeric primitives (`+ - * < > <= >=`) emit native Janet ops, and
-  unchanged.
+calls compile to direct Janet calls.
-- **Everything else compiles to Janet.** The form is macro-expanded, lowered to
-  a Janet AST, and `eval`'d in a **per-context Janet environment**. `def`/`defn`
-  bindings live in that environment so they persist and resolve across forms
-  (and self-recurse via a named-fn rewrite); hot numeric primitives
-  (`+ - * < > <= >=`) emit native Janet ops so the JIT-free Janet VM runs them at
-  full speed; and function calls compile to direct Janet calls (keyword/map/set
-  in call position still dispatch through the IFn runtime).
-
-The two paths **share one context.** Compiled `def`/`defn` results are both
-evaluated into the Janet environment *and* interned into the Jolt namespace, so
-an interpreted form can call a compiled function and vice-versa within the same
-context — which is what makes the always-interpret carve-out above safe.
 
 ```janet
 (def ctx (init {:compile? true}))
 (eval-string ctx "(defn fib [n] (if (< n 2) n (+ (fib (- n 1)) (fib (- n 2)))))")
-(eval-string ctx "(fib 30)")   ; → 832040, fast
+(eval-string ctx "(fib 30)")   ; → 832040, native Janet bytecode
 ```
 
-For compute-heavy code the compiled path is dramatically faster — recursive
+For compute-heavy code the compiled path is dramatically faster than tree-walking,
-`fib(30)` runs in ~0.08 s compiled vs ~50 s interpreted (≈600×), at native Janet
+at native Janet speed.
-speed.
 
-Compile mode is opt-in and still maturing. The numeric-op inlining relaxes the
+**Validated at parity.** The conformance suite passes 218/218 under *both*
-strict non-number checks (e.g. `(< nil 1)` doesn't throw), and constructs the
+interpreter and compiler (`conformance-test.janet` runs both in CI), and the full
-compiler doesn't yet handle currently **error** rather than transparently
+clojure-test-suite under compilation matches the interpreter baseline across
-falling back to the interpreter — a per-form hybrid fallback (compile what we
+~4.6k assertions — evidence the hybrid path doesn't diverge.
-can, interpret the rest) is the next step toward making compilation safe to
+
-turn on by default.
+**AOT.** `aot.janet` marshals a compiled namespace to a Janet bytecode image
+(`save-ns`) and loads it back into a fresh context (`load-ns-image`), skipping
+parse/analyze/emit/compile on reload. Core fns are referenced by name against the
+baked-in runtime; only user bytecode and var cells are serialized.
 
 ## Host interop
 

doc/self-hosting-compiler.md

@@ -26,12 +26,25 @@ prior art, the constraints we verified, and a recommended path.
   tree-walking interpreter (`evaluator.janet`); ~1k lines of **Clojure** are the
   stdlib (`clojure.string/set/walk/…`, `jolt.*`). So the language is mostly in
   the host, inverted from the Clojure-in-Clojure ideal.
-- The interpreter (`eval-form`) is the live, complete path.
+- The interpreter (`eval-form`) is the complete reference path.
-- There's an opt-in compiler (`compiler.janet`): `analyze-form` (reader form →
+- The compiler (`compiler.janet`) — `analyze-form` (reader form → `:op` AST) →
-  AST tagged with `:op`) → `emit` (AST → Janet form) → Janet `compile`/`eval`.
+  `emit` (AST → Janet form) → Janet `compile`/`eval` — is now **on by default**
-  Phases 1–2 are done (per-context env so defs persist and resolve; native
+  in the shipped runtime (`JOLT_INTERPRET=1` opts out). It is a *hybrid*: forms
-  arithmetic ops + direct calls — recursive `fib(30)` ≈ 0.08 s). Phase 3
+  it can't compile correctly throw `jolt/uncompilable` and fall back to the
-  (destructuring, multi-arity, hybrid fallback) is open.
+  interpreter (`loader/eval-toplevel`), so results always match the interpreter.
+  Validated at parity — conformance 218/218 under both interpret and compile, and
+  the clojure-test-suite under compile passes 3932 (vs the 3913 interpreter
+  baseline) across ~4.6k assertions.
+- Done so far: var-indirection (globals deref through var cells, so compiled code
+  is REPL-redefinable); hybrid fallback; compilation of multi-arity / named /
+  variadic fns and `recur` inside `fn`; map and vector literal compilation
+  (mode-correct via `make-vec` / `build-map-literal`); resolution that mirrors
+  the interpreter (current ns → `clojure.core` → Janet-env fallback); and AOT
+  (`aot.janet`) that marshals a compiled namespace to a Janet bytecode image
+  against the baked-in runtime dictionary and loads it back.
+- Still open — the actual self-hosting: the compiler and most of `clojure.core`
+  are still Janet. Rewriting them in Clojure (compiled by Jolt) is the remaining
+  Clojure-in-Clojure work.
 
 ## What the host gives us (verified)
 
@@ -130,23 +143,28 @@ coverage incrementally, and de-risks the self-hosting bootstrap.
 `def` updates the root; protocol/multimethod dispatch stays dynamic. Direct
 linking is opt-in, never the default, so the REPL is always live.
 
-## A staged path (maps onto the existing beads)
+## A staged path
 
-1. **Var-indirection in the emitter** *(new, foundational — do before more
+1. **Var-indirection in the emitter** — *done*. Global refs compile as var-cell
-   compiler work)*. Compile global refs as var-cell derefs; verify a compiled
+   derefs, so a compiled `defn` is redefinable at the REPL.
-   `defn` is redefinable at the REPL. Without this, more compiler coverage just
+2. **Hybrid fallback + coverage** (`jolt-1bj`) — *done*. Forms the compiler can't
-   bakes in more early-binding to undo later.
+   compile throw `jolt/uncompilable` and fall back to the interpreter, so compile
-2. **Hybrid fallback + finish coverage** (`jolt-1bj`, Phase 3): per-form fallback
+   mode is always correct. Covered: multi-arity/named/variadic fns, `recur` in
-   to `eval-form`; then compile destructuring, multi-arity/variadic, and the
+   `fn`, map/vector literals, and resolution matching the interpreter. (One
-   remaining forms as optimizations on top of the always-correct fallback.
+   optimization left: compile destructuring via a shared `destructure` expander
-3. **Self-host the compiler.** Rewrite `compiler.janet` as Clojure (`jolt.compiler`)
+   instead of falling back — `jolt-7dl`.)
-   that Jolt compiles. Now the compiler is part of the language it compiles.
+5. **Compile-by-default + AOT** (`jolt-7j9`) — *done, done out of order*. Once the
-4. **Shrink the kernel / core-in-Clojure.** Move `clojure.core` from Janet to
+   hybrid path was validated at parity, compilation was flipped on by default and
-   Clojure incrementally, leaving only the minimal kernel in Janet. Each moved
+   AOT images (`aot.janet`) landed. Done before 3–4 because it's the runtime
-   piece is compiled by the previous stage — the language building itself.
+   payoff and only needed the hybrid path to be correct, not self-hosting.
-5. **Compile-by-default + AOT** (`jolt-7j9`, Phase 4): once the hybrid path is
+3. **Self-host the compiler** (`jolt-lcn`) — *open*. Rewrite `compiler.janet` as
-   robust, flip compilation on by default; ship AOT images via `make-image`.
+   Clojure (`jolt.compiler`) that Jolt compiles. Now the compiler is part of the
+   language it compiles.
+4. **Shrink the kernel / core-in-Clojure** (`jolt-uqi`) — *open*. Move
+   `clojure.core` from Janet to Clojure incrementally, each piece compiled by the
+   previous stage — the language building itself — leaving a minimal Janet kernel.
 
-The ordering matters: var-indirection first (correctness for redefinition), then
+What remains (3 and 4) is the actual Clojure-in-Clojure rewrite: the largest part
-the hybrid fallback (correctness for coverage), then self-hosting and kernel
+of the work and where the "language builds itself" payoff lives. The correctness
-shrinking (the Clojure-in-Clojure payoff), then default-on + AOT.
+and runtime foundations it needs — redefinable compiled code, an always-correct
+hybrid path, compile-by-default, and AOT — are now in place.